Thanks for your interest in my predictions, as you said you have not heard of these coins that means you are not studying them so please do not make sweeping predictions i can explain why i choose these coins out of so many coins listed in exchange.
To the second part of your question I just want to say that holding bitcoin is probably the best strategy if you are looking for long term investment.
But again the risk is big if you put your whole investment into bitcoin only.
What you need to do is diversify your portfolio by trading multiple coins that will not only safeguard you against the sudden market collapse but also increase you risk reward ratio......